<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>我的第一个项目</title>
    <style>
    	div{
    		width: 200px;
    		height: 200px;
    		background-color: red;
    		margin: 50px auto;
    	}
    </style>
</head>

<body>
    <div id="">
    	
    </div>
</body>

</html>